I've only had it once and it was on the rocks and not in a tasting glass. I wasn't as impressed with it as the 17 and 18 years which were Stitzel Weller stock. The 21 is their own stock. It was good, but I'm not sure it deserves all the hype around it (which I think is largely lasting hype from the others). I probably wouldn't buy it for over $100 but that's what it's mostly fetching.

At 134 proof, it's got some heat to it, and one of the darkest colored bourbon's I've seen...but after one cube and a tiny splash of water to open it up, it's excellent. Deepest notes besides the initial oaky flavor were cinnamon & a hint of chocolate.